Changing Roughness value in python script has no effect
Aha!
So in case anyone else comes across this
to debug this I checked the property path by right clicking in blender on the property and selected &quot;copy data path&quot; which gave me this value:
nodes[&quot;Principled BSDF&quot;].inputs[7].default_value

So I updated my script accordingly:
for m in bpy.data.materials:
m.node_tree.nodes[&quot;Principled BSDF&quot;].inputs[7].default_value = 1